Our End User Terms (Clause 2) state a customer ordering fibre broadband is responsible for gaining written consent from the owners of the property, if they are not the owner.
“If you do not own your premises (or are not the only owner, unless you are a joint owner), you must ensure that the owner(s) give us written consent to install, locate, access, maintain, operate and own our network on that premises. You will be responsible to us for any loss we suffer if you do not ensure this. You also agree that, if asked, you will provide us with written evidence of that consent.”
You will need to speak to your tenants regarding this matter.